2022 day 6 init + bash part 1

2022/day06/aoc.bash

@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+#
+# aoc.bash: Advent of Code 2022, day 6
+#
+# Copyright (C) 2022 Bruno Raoult ("br")
+# Licensed under the GNU General Public License v3.0 or later.
+# Some rights reserved. See COPYING.
+#
+# You should have received a copy of the GNU General Public License along with this
+# program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+
+. common.bash
+
+declare -a stacks=() rules=()
+
+parse() {
+    local -i _queue _state=1
+    local _input
+    local -a _parse
+    local cur=""
+    local -i lcur=0 i
+
+    read -r _input
+    len=${#_input}
+
+    lcur=0
+    for (( i = 0; i < len - 4; ++i )); do
+        echo
+        nextc=${_input:i:1}                       # get next char
+        printf "next=%s cur=%s lcur=%d\n" "$nextc" "$cur" "$lcur"
+        for ((j = 0; j < lcur; ++j)); do          # compare with previous ones
+            printf "compare %s with %d:%s\n" "$nextc" "$j" "${cur:j:1}"
+            if [[ $nextc == "${cur:j:1}" ]]; then
+                cur=${cur:j+1}$nextc
+                (( lcur = lcur - (j + 1) + 1))
+                printf "\t-> equal cur=%d:%s" "$lcur" "$cur"
+                continue 2
+            fi
+        done
+        cur+=$nextc
+        ((lcur++))
+        ((lcur == 4)) && break
+    done
+    echo "$cur" $((i + 1))
+}
+
+solve() {
+    local -i _part="$1" _i=0 _j=0 _nb _from _to
+    local -a _rule
+
+    for ((; _i < ${#rules[@]}; ++_i )); do
+        read -ra _rule <<< "${rules[$_i]}"
+        (( _nb = _rule[0], _from = _rule[1] - 1, _to = _rule[2] - 1 ))
+        if ((_part == 1)); then
+            # move elements one by one
+            for ((_j = 0; _j < _nb; ++_j)); do
+                stacks[$_to]="${stacks[$_from]:0:1}${stacks[$_to]}"
+                stacks[$_from]=${stacks[$_from]:1}
+            done
+        else
+            # move elements by block
+            stacks[$_to]="${stacks[$_from]:0:_nb}${stacks[$_to]}"
+            stacks[$_from]=${stacks[$_from]:_nb}
+        fi
+    done
+    printf -v res "%c" "${stacks[@]}"
+}
+
+main "$@"
+exit 0